Journal articles on the topic 'Sand retention'
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1
Wang, Dongmei, Chunxiao Li, and Randall S. Seright. "Laboratory Evaluation of Polymer Retention in a Heavy Oil Sand for a Polymer Flooding Application on Alaska's North Slope." SPE Journal 25, no. 04 (May 14, 2020): 1842–56. http://dx.doi.org/10.2118/200428-pa.
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Summary For a polymer flooding field trial in a heavy oil reservoir on Alaska's North Slope, polymer retention is a key parameter. Because of the economic impact of retention, this parameter was extensively studied using field core material and conditions. In this paper, multiple types of laboratory measurements were used to assess hydrolyzed polyacrylamides (HPAM) polymer retention, including a brine tracer, effluent viscosity, total effluent organic carbon, and effluent chemiluminescent nitrogen. Retention tests were conducted in different Milne Point Schrader Bluff sands, with extensive permeability, grain size distribution, X-ray-diffraction (XRD), and X-ray fluorescence (XRF) characterizations. Several important findings were noted. Polymer retention based on effluent viscosity measurements can be overestimated unless the correct (nonlinear) relation between polymer concentration and viscosity is used. Polymer degradation (either mechanical or oxidative) can also lead viscosity-based measurements to overestimate retention. Inaccessible pore volume (PV) (IAPV) can be overestimated if insufficient brine is flushed through the sand between polymer banks. Around 100 PVs of brine may be needed to displace mobile polymer to approach a true residual resistance factor and properly measure IAPV. Even for a sandpack with kwsor = 20 md, IAPV was zero for HPAM with a molecular weight (Mw) of 18 MM g/mol. Fine-grained particles (<20 µm) strongly impacted polymer retention values. Native NB#1 sand with a significant component of particles <20 µm exhibited 290 µg/g, while the same sand exhibited 28 µg/g after these small particles were removed. Polymer retention did not necessarily correlate with mineral composition. The NB#1, NB#3, and OA sands had similar elemental and clay compositions, but the NB#1 sand exhibited ∼10 times higher retention than the NB#3 sand. Polymer retention did not necessarily correlate with permeability. NB#1 sand exhibited much higher retention than OA sand, even though NB#1 sand was twice as permeable as OA sand. No evidence of chromatographic separation of HPAM molecular weights was found in our experiments. Although retention tended to be greater without a residual oil saturation (than at Sor), the effect was not strong. Aging a core (with high oil saturation) at 60°C reduced HPAM retention by a factor of two. Under similar conditions, polymer retention was greater for a higher Mw HPAM (18 MM g/mol) than for a lower Mw HPAM (10 to 12 MM g/mol). In many cases with high polymer retention values (e.g., 240 µg/g), polymer arrival at the end of the core was relatively quick, but achieving the injected concentration occurred gradually over many PVs. This effect was not caused by chromatographic separation of polymer molecular weights. Results from modeling of this behavior were consistent with concentration-dependent polymer retention. The form assumed for the retention function in a simulator can have an important impact on the timing and magnitude of the oil response from a polymer flood. Field-based observations can underestimate polymer retention, depending on when the tracer and polymer concentrations were measured and the assumptions made about reservoir heterogeneity.
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Feng, Yuqing, Xavier Choi, Bailin Wu, Qinggong Wang, Chong Yau Wong, Seng Lim, Bahrom Madon, et al. "A numerical assessment of the effect of particle size distribution and operation parameters on sand retention over sand screens." APPEA Journal 55, no. 2 (2015): 476. http://dx.doi.org/10.1071/aj14111.
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Sand screens are often installed in sanding prone wellbores to control sand production. A selection of optimal sand screen apertures is required to minimise sand production and maximise fluid production. This has been accomplished historically on empirical correlations, rules of thumb and laboratory sand retention experiments. These methodologies have a number of limitations that can lead to different screen types and sub-optimal screen apertures to be selected. Using discrete element models (DEMs), many design/operating parameters similar to a specific wellbore condition can be simulated and tested in parallel. Most importantly, the detailed particle scale information helps to give a detailed understanding of the underlying mechanisms controlling the sand retention process. This extended abstract presents an investigation of the sand production problem from wire wrapped screens and slotted liners through the use of a DEM for the solid flow with fluid flow coupling using computational fluid dynamics (CFD). Information about particle sizes and distributions incorporated in the DEM model are based on measurement data from reservoir sands. The focus is on the effect of particle size distributions, particle concentration, and the slot width on sand retention across a slotted sand screen.
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Hunt, H. W., A. M. Treonis, D. H. Wall, and R. A. Virginia. "A mathematical model for variation in water-retention curves among sandy soils." Antarctic Science 19, no. 4 (October 1, 2007): 427–36. http://dx.doi.org/10.1017/s0954102007000703.
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AbstractEquations were developed to predict soil matric potential as a function of soil water content, texture and bulk density in sandy soils. The equations were based on the additivity hypothesis - that water-retention of a whole soil depends on the proportions of several particle size fractions, each with fixed water-retention characteristics. The new model is an advancement over previously published models in that it embodies three basic properties of water-retention curves: a) matric potential is zero at saturation water content, b) matric potential approaches -∞ as water content approaches zero, and c) volumetric water content in dry soil is proportional to bulk density. Values of model parameters were taken from the literature, or estimated by fitting model predictions to data for sandy soils with low organic matter content. Most of the variation in water-release curves in the calibration data was explained by texture, with negligible effects of bulk density and sand particle size. The model predicted that variation in clay content among soils within the sand and loamy sand textural classes had substantial effects on water-retention curves. An understanding of how variation in texture among sandy soils contributes to matric potential is necessary for interpreting biological activity in arid environments.
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Rahayu, Rahayu, Yang Geun Mo, and Choi Joon Soo. "Amendements on Salinity and Water Retention of Sand Base Rootzone and Turfgrass Yield." SAINS TANAH - Journal of Soil Science and Agroclimatology 16, no. 1 (June 30, 2019): 103. http://dx.doi.org/10.20961/stjssa.v16i1.28132.
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This research was column pot experiment with turfgrass was Kentucky bluegrass (<em>Poa pratensis</em>) plant irrigated saline irrigation and the column soaked in saline water. Rootzone profile consisted of 20 cm using saline lake dredged up sand. The sand amendments of the root zone were soil, zeolite, bottom ash, and peat. The mixtures of topsoil were; 90% sand + 10% peat moss, 80% sand + 10% soil + 10 % bottom ash, 80% sand + 20% soil, 90% sand + 5% peat + 5% zeolite, and 80% sand + 20% bottom ash. Interruption layer with coarse sand with diameters over 2 mm of 20 cm and 10 cm loamy soil as the bottom layer of the column. The result showed that Kentucky bluegrass could grow in sand based growing media amended by peat, sandy loam soils, bottom ash and zeolite being irrigated by 2 dS m<sup>-1</sup> saline water. Sand-based growing media amended by peat resulted in the highest clipping weigh but showed the highest salt accumulations. Sand amended by bottom ash and applied gypsum decreased clipping weigh, decreased SAR and increased calcium (Ca) when compared to the soil + peat (SP). Sand amended by zeolite and gypsum decreased clipping weight, decreased sodium adsorption ratio (SAR) and higher Ca. Higher soil moisture retention of growing media promoted the growth of Kentucky bluegrass in spring, and lower moisture content promoted the growth in summer and fall season.
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Wei, Wenjun, Bing Wang, and Xiang Niu. "Soil Erosion Reduction by Grain for Green Project in Desertification Areas of Northern China." Forests 11, no. 4 (April 22, 2020): 473. http://dx.doi.org/10.3390/f11040473.
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The Grain for Green Project (GGP) encompasses most desertification areas in northern China where fragile soils are susceptible to erosion given the arid and semi-arid climate, low vegetation cover, and strong winds. We collected relevant data through ecological surveys and literature review to quantify total sand fixation and dust retention in 2015 based on different restoration methods, forest types, ecological function zones, and key desertification areas. Our results showed that cropland and wasteland afforestation increased sand fixation and dust retention, whereas facilitate afforestation was less effective in doing so. Further, sand fixation and dust retention values were higher in ecological and shrub forests compared with economic forests, as well as in wind erosion zones compared with wind-water erosion and water erosion zones. Moreover, 43.28% and 44.75% of total sand fixation and dust retention, respectively, were concentrated in important windbreak and sand fixation areas. Similarly, 60% and 30% of total sand fixation and dust retention, respectively, occurred in sandstorm paths and sources. Lastly, policy factors primarily influenced the spatial distribution patterns of both sand fixation and dust retention. Based on these results, enhancement of GGP efficacy into the future will rely on increased restoration efforts specifically aimed at planting more drought-resistant shrubs and native vegetation as doing so will enhance sand fixation, dust retention, and thus, the ecological integrity of these valuable and fragile desert ecosystems in northern China.
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Murdoch, Charles L., and David L. Hensley. "Physical Properties of Hawaiian Golf Course Sands." HortTechnology 4, no. 2 (April 1994): 150–53. http://dx.doi.org/10.21273/horttech.4.2.150.
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Physical properties (particle size distribution, bulk density, capillary pore space, non-capillary pore space, hydraulic conductivity, and water retention) of three imported silica sands (Perth, Malaysian, and Newcastle), a man-made sand product (Mansand), and coral sand alone and in peatmoss mixtures were determined to evaluate their suitability as golf-green substrates. Based on laboratory evaluation of physical properties, the silica sands amended with peatmoss (15%) were superior to coral sand or crushed basalt (Mansand) amended with 15% peatmoss for use in high-traffic turfgrass areas.
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Carpenter, Chris. "Evaluating Sand-Screen Performance With Sand-Retention Tests and Numerical Modeling." Journal of Petroleum Technology 68, no. 10 (October 1, 2016): 76–78. http://dx.doi.org/10.2118/1016-0076-jpt.
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Ismail, Noor Ilyana, Shibo Kuang, Mengmeng Zhou, and Aibing Yu. "Numerical investigation of non-uniform sand retention behavior in sand screens." Powder Technology 395 (January 2022): 604–17. http://dx.doi.org/10.1016/j.powtec.2021.10.016.
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Wulandari, Lies Kurniawati, and Munasih Munasih. "Blackwater Purification Using Sand Filter." Journal of Applied Philosophical Management and Innovation 1, no. 1 (December 9, 2018): 35. http://dx.doi.org/10.26805/japmai.v1i1.19.
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This study aimed to determine the effect of the thickness of the sand filter and the best residence time for water purification. The type of sand used in this study was concrete sand, and the observation was focused on turbidity (NTU) parameter. Measurements of turbidity were performed before treatment, as well as at each retention time from 1 to 9 days. The method of data analysis was Linear Regression analysis on SPSS 21 program. Blackwater was collected in the morning and afternoon, and the turbidity of each sample was 1000 and 800 NTU, respectively. Wastewater turbidity was continued to decreased along with the longer retention time. The best results were obtained from the treatment 3 (sand filter 20 cm) with 9 days retention time, in which the turbidity levels decreased to 90 NTU (morning sample), and 105 NTU (afternoon sample).
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Nguyen, Lam Quoc Cuong, and Mau Dang Nguyen. "Evaluating the screen performance in sand control design by laboratory sand retention test." Petrovietnam Journal 11 (December 16, 2022): 43–49. http://dx.doi.org/10.47800/pvj.2022.11-04.
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To produce oil and gas from unconsolidated sandstone reservoirs, sand screens are necessary to control sand flowing from the formation into the wells, causing well pluggings. In open hole completion, stand-alone sand screen is an essential component to prevent sand production, thus, selection of suitable sand screens is critical to minimize sand production and optimize the well’s production life.
Nowadays, premium screens with steel meshes make the openings of the screen slots complex in shape, resulting in a very different effect of sand retention compared to the traditional screens. The sand retention test is considered a standard and must be conducted to select screen opening and size, which decides the sand prevention capacity of the screen.
The paper presents the factors affecting the results of laboratory sand retention tests and proposes solution in the direction of considering the data trend rather than relying completely on the output results. The paper also brings about the evaluation method through the change the screen’s permeability to have better qualitative results compared to the traditional methods.
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Ferguson, G. A., and I. L. Pepper. "Ammonium Retention in Sand Amended with Clinoptilolite." Soil Science Society of America Journal 51, no. 1 (January 1987): 231–34. http://dx.doi.org/10.2136/sssaj1987.03615995005100010047x.
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Liu, Junliang, Weipu Xu, Qingjian Zhao, Mingqi Qiao, Huiyun Zhang, and Gang Chen. "Bacterial Retention in Lipopolysaccharide Coated Silica Sand." Separation Science and Technology 42, no. 5 (March 2007): 1031–47. http://dx.doi.org/10.1080/01496390601120672.
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Henderson, Janet C., and David L. Hensley. "Ammonium and Nitrate Retention by a Hydrophilic Gel." HortScience 20, no. 4 (August 1985): 667–68. http://dx.doi.org/10.21273/hortsci.20.4.667.
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Abstract Studies were conducted to determine if ammonium or nitrate were retained by a starch-polyacrylamide hydrophilic gel. Silicia sand was amended with 0, 2, 3, and 4 kg/m3 hydrophilic gel. Ammonium nitrate solution was applied to dry and distilled water-saturated amended sand in pots. The amended medium was washed with distilled water, leachate was collected, and ammonium and nitrate contents were determined. More ammonium was retained by all concentrations of hydrophilic gel-amended sand than in sand alone, especially in media not saturated prior to application. Nitrate was not retained in large amounts by any medium.
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Bolster, Carl H. "Role of sand size on bacterial retention in biochar-amended sand filters." Biochar 1, no. 4 (December 2019): 353–63. http://dx.doi.org/10.1007/s42773-019-00027-0.
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Gaiser, Thomas, Frieder Graef, and José Carvalho Cordeiro. "Water retention characteristics of soils with contrasting clay mineral composition in semi-arid tropical regions." Soil Research 38, no. 3 (2000): 523. http://dx.doi.org/10.1071/sr99001.
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In semi-arid tropical regions, the availability of reliable data for water retention in relation to soil type, texture, and organic matter content is low. It would be therefore desirable to develop pedotransfer functions (PTF) in order to estimate water retention characteristics from easily available soil parameters. In the present study, a soil database containing water retention characteristics, particle size distribution, and total organic carbon content of 663 horizons from semi-arid regions in NE Brazil and SE Niger was used to investigate the effect of contrasting clay mineral composition on water retention and PTF characteristics for soils from semi-arid tropical regions. For soil water content at field capacity (–33 kPa) and wilting point (–1500 kPa), PTFs were established and validated with disturbed samples from LAC soils (soils containing predominantly low activity clay; CEC < 24 cmol/kg clay) and non-LAC soils. The PTFs for the LAC soil group differed considerably from the PTFs for non-LAC soils with respect to the contribution of total organic carbon and silt content to the prediction of soil water content at field capacity and wilting point. For the particle size classes sand, loamy sand, sandy loam, and sandy clay loam, the mean measured soil water contents in LAC soils were significantly smaller than in non-LAC soils at a matric potential of –33 kPa. The results demonstrate the influence of clay mineral composition on soil water retention and its importance for the development of pedotransfer functions.
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Pan, Yuan, Ze Yang, Yuting Pan, Yiwen Xu, and Ruiquan Liao. "Research on Conductivity Damage Based on Response Surface Analysis." Energies 15, no. 8 (April 12, 2022): 2818. http://dx.doi.org/10.3390/en15082818.
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Hydraulic fracturing is an important means of developing unconventional oil and gas layers. The fracture conductivity of tight sandstone reservoirs after fracture is affected by many factors, such as the interaction between the fracturing fluid, water, and rocks; the fracturing materials; and the construction parameters. This paper improves the experimental process of the long-term conductivity test and provides insight into conductivity prediction and optimization based on the response surface test method. The test process is conducted in the following manner: (1) inject nitrogen to evaluate the fracture conductivity before fracturing fluid damage; (2) inject fracturing fluid to simulate shut-in; and (3) inject nitrogen again to evaluate fracture conductivity after the damage ability of the fracturing fluid. The single factor test results show that the lower the sand concentration is, the higher the fracturing fluid viscosity will be, and the longer the fracturing fluid retention time is, the greater the damage to the conductivity of the fracturing fluid will be. The response surface test results show that the order of factors affecting the retention of conductivity is fracturing fluid viscosity > sand concentration > fracturing fluid retention time. There is a certain interaction between sand concentration and fluid viscosity, and there is also a certain interaction between fluid viscosity and fluid retention time, but these interactions are not significant; when the fracturing fluid retention time is longer, there will be an interaction between the sand concentration and the fracturing fluid retention time. In addition, based on the model used to optimize the fracturing construction parameters from the perspective of proppant conductivity damage, the optimal solution is when the viscosity of the fracturing fluid is 1 mPa.s, the paved-sand content is 8.49 kg/m2, and the retention time of the fracturing fluid is 10 h. The maximum retention rate of the flow conductivity is 63.19%.
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Raj, John Kuna. "Soil Moisture Retention Characteristics Of Saprock From The Weathering Profile Over A Biotite-Muscovite Granite In Peninsular Malaysia." Warta Geologi 47, no. 3 (December 29, 2021): 217–25. http://dx.doi.org/10.7186/wg473202104.
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The weathering profile at the slope cut near Km 16 of the Kuala Lumpur - Ipoh trunk road can be differentiated into an upper, 11.8 m thick pedological soil (zone I) and a lower, 31.9 m thick saprock (zone II) comprising silty sandy gravels that distinctly preserve the minerals, textures and structures of the original granite. In order to investigate the influence of particle size distributions on soil moisture retention characteristics, saprock samples were collected at depths of 26.53 m (Sample A), 31.29 m (Sample B) and 41.93 m (Sample C). Samples A and B, with porosities of 37%, comprise 33% gravel, 27% sand, 22% silt and 18% clay, and 31% gravel, 24% sand, 25% silt and 22% clay, respectively. Sample C with a porosity of 44% consists of 24% gravel, 28% sand, 38% silt and 10% clay. Tests with the pressure plate method show increasing suctions from 0 kPa through 0.98 kPa and 9.8 kPa to 33 kPa and 1,500 kPa to result in gravimetric soil moisture retentions of 31.9% through 28.6% and 23.3% to 16.9% and 6.8% in sample A, of 32.1% through 24.9% and 21.5% to 17.8% and 7.4% in sample B, and of 31.5% through 30.3% and 27.30% to 23.5% and 9.5% in sample C. Regression analyses of gravel, sand and clay contents plotted against moisture contents retained at high suctions (33 kPa and 1,500 kPa) yield negative trends with variable correlation coefficients (R2), though plots involving silt contents yield positive trends with large correlation coefficients (R2 >0.9966). It is concluded that adsorption of water on surfaces of silt sized particles (of mainly sericite derived from weathering of feldspars) that gives rise to the retention of soil moisture in saprock.
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Panthi, Sunny, Kusum Dutta, and Gaurav Singla. "Evaluation of Effect by Different Surface Treatment Agents on Retention of Custom Made Cast Metal Post and Prefabricated Glass Fibre Post-A Comparative Study." Dental Journal of Advance Studies 03, no. 01 (April 2015): 007–11. http://dx.doi.org/10.1055/s-0038-1672007.
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AbstractPosts are widely used for restoring endodontically treated teeth with insufficient coronal tooth structure. Custom made cast metal post and core systems have a long history of successful use due to their superior physical properties. Prefabricated post systems have recently become more popular because they can provide satisfactory results, while saving time and reducing costs. Materials and Method: Post spaces were prepared in 60 extracted caries free teeth, and divided into two main groups of 30 teeth each for cast metal and glass fibre posts. These groups were further divided into 3 subgroups of 10 specimens each I) Control group without any surface treatment, II) Specimens treated with 57% ethanol, III) Specimens air abraded with 50um air borne alumina particles. Teeth were mounted in acrylic blocks prepared from a specially fabricated metal device. Posts were luted in the prepared post spaces with glass ionomer luting cement. Retentive strength was tested by Universal testing machine at 2mm/min crosshead speed. Results: Sand blasting of cast metal posts showed more significant improvement in retention compared to both control group and ethyl alcohol treated groups. In case of glass fibre posts, sand blasting significantly improved its retention compared to control group but no significant difference was observed between control and ethyl alcohol treated groups. There was also no significant difference between ethyl alcohol treated and sand blasted group. Conclusion: It was concluded that, sand blasting is an effective method to improve retention of both cast metal and glass fibre posts.
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Vidler, Andrew, Olivier Buzzi, and Stephen Fityus. "The Significance of Hydrophobicity for the Water Retention Properties of Sand and Coal." Applied Sciences 11, no. 13 (June 26, 2021): 5966. http://dx.doi.org/10.3390/app11135966.
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For mine wastes such as coal tailings, management of these materials requires complex geotechnical engineering that uses many soil properties, such as water retention. However, coal itself is chemically heterogeneous and often appears to be partially hydrophobic, which affects its water retention properties. This study aims to outline how hydrophobic soil particles and coal alter water retention curves compared to hydrophilic materials. The study involves four materials: sand, hydrophobized sand, crushed rock and crushed coal. Mixtures of sand with different proportions of hydrophobic particles had their water retention curves measured and compared, with the only variable being the particle surface characteristics. The rock and coal were separated into different particle size fractions and had their water retention curves measured and compared, with the only variable being particle hydrophobicity. A clear trend was observed for the sand mixtures: the degree of saturation at any suction was reduced when increasing the hydrophobicity of the material. This trend indicates the fundamental water retention behavior expected for soils more hydrophobic than is typical, which was not clearly demonstrated in previous studies. However, a similar trend was not seen when comparing the rock and otherwise identical hydrophobic coal samples, which actually appeared hydrophilic in terms of water retention. ESEM imaging shows a dual hydrophilic and hydrophobic behavior for coal which may explain the result. However, further research is required to understand the discrepancy, which appears to be caused by an unknown coal–water phenomena.
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Moskal, T. D., L. Leskiw, M. A. Naeth, and D. S. Chanasyk. "Effect of organic carbon (peat) on moisture retention of peat:mineral mixes." Canadian Journal of Soil Science 81, no. 2 (May 1, 2001): 205–11. http://dx.doi.org/10.4141/s00-011.
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Quantification of the effects of organic carbon (OC) addition to reclaimed soils is an important reclamation issue. Such effects on soil texture, field capacity (FC), wilting point (PWP) and water-holding capacity (WHC), all expressed both on a gravimetric and volumetric basis, were quantified using both in situ soil samples and laboratory-prepared peat:mineral mixes. Soil samples were collected from both natural and reclaimed areas within the Oil Sands region of Alberta; peat was obtained from the same area. Organic carbon was determined for laboratory-created mixtures and expressed as volume ratios; for the in situ samples it was expressed as % OC. Bulk density, an important factor in the effects of OC on water retention, was measured in situ.Water retention parameters of in situ samples on a gravimetric basis were significantly related to % OC, but those on a volume basis were not. Trends in volumetric WHC for in situ, coarse-textured samples were similar to those for gravimeteric WHC, due to similar bulk densities ranging from 1.30 to 1.40 Mg m–3. However, for in situ peaty soils, trends in volumetric water retention did not mimic those expressed on a gravimetric basis due to low and irregular bulk densities. For laboratory-constructed peat:mineral mixes, FC and WHC were significantly impacted by % OC, however, PWP was not. The addition of peat material resulted in minor textural changes for sand and loamy sand; hence, the change in texture could not be responsible for the increases in WHC as the result of peat additions. The results for sandy loam were variable. Key words: Bulk density, field capacity, reclamation, water-holding capacity
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Harris, W. G., M. Chrysostome, T. A. Obreza, and V. D. Nair. "Soil Properties Pertinent to Horticulture in Florida." HortTechnology 20, no. 1 (February 2010): 10–18. http://dx.doi.org/10.21273/horttech.20.1.10.
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Horticulture is an important industry in Florida despite formidable soil limitations. Favorable climate often makes the expense of overcoming these limitations economically feasible. Challenges arise from high water tables and/or sandy textures, both of which limit plant-available water and nutrient retention. High water tables of flatwoods (Spodosols) and marshes (Everglades Histosols) restrict root proliferation and commonly require artificial drainage. Upper zones of these soils are dominated by uncoated sand (Spodosols) or organic matter (Histosols) that has minimal sorption capacity for phosphorus (P) such that its transport poses an environmental risk without careful management. Nitrogen can be lost via denitrification under prolonged near-surface water saturation. At the other extreme but also prevalent in Florida are excessively well-drained sandy “sandhills” soils with limited water and nutrient retention. Nitrogen leaching from the latter soils can result in nitrate contamination in groundwater. Soil morphology is an important consideration in gauging nutrient and moisture retention. For example, each is enhanced by the presence of sand-grain coatings. Some amendments show promise in reducing P and moisture loss from sandy soils. Precarious balance between horticultural production and environmental risks for Florida soils has spurred development of approaches providing for a more accurate determination of the safe soil P storage capacity. Testing and refinement of these approaches are needed.
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Razavi, Fatemeh, Alexandra Komrakova, and Carlos F. Lange. "CFD–DEM Simulation of Sand-Retention Mechanisms in Slurry Flow." Energies 14, no. 13 (June 24, 2021): 3797. http://dx.doi.org/10.3390/en14133797.
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The primary motivation of this paper is to investigate the sand-retention mechanisms that occur at the opening of sand filters. Various retention mechanisms under various conditions are explored that have a particulate flow with a low concentration of sand particles (called slurry flow) such as particle shape, size, and concentration. The computational fluid dynamic (CFD)–discrete element method (DEM) model is applied to predict the retention mechanisms under steady flow conditions of the well-bore. By using coupled CFD–DEM (CFD to model the fluid flow, and DEM to model the particle flow), the physics involved in the retention mechanisms is studied. The coarse grid unresolved and the smoothed unresolved (refined grid unresolved) coupling approaches implemented in STAR-CCM+ (SIEMENS PLM) are used to transfer data between the fluid and solid phases and calculate the forces. The filter slots under investigation have different geometries: straight, keystone, wire-wrapped screen (WWS) and seamed slot and the particles are considered with different shapes and different aspect ratios and size distributions. The flow regime is laminar in all simulations conducted. The CFD–DEM model is validated from the perspectives of particle–fluid, particle–particle, and particle–wall interactions. Verification of the CFD–DEM model is conducted by mesh sensitivity analysis to investigate the coupling resolution between the CFD and DEM. By simulation of numerous slurry flow scenarios, three retention mechanisms including surface deposition, size exclusion, and sequential arching of particles are observed. However, the concentration of particles is too diluted to result in multiparticle arch formation. In the simulations, various conditions are tested to give us an insight into the parameters and conditions that could affect the occurrence of the retention mechanisms. As an example, the importance of the gravity force and interaction forces on retention mechanisms are confirmed at the microscale in comparison with others forces involved in retention mechanisms such as the drag force, lift force, cohesive force, buoyancy force, and virtual mass force.
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Li, Jiu Yi, Xiao Kang Zhao, Xiu Jun Tian, Jin Li, Li Jing Wang, Yan Yu Zhang, Xu Zhang, Yu Chen, and Ai Min Wang. "Effects of Retention in Effluent from a Wastewater Treatment Plant on Deposition of Escherichia coli in Packed-Bed Columns." Advanced Materials Research 955-959 (June 2014): 951–55. http://dx.doi.org/10.4028/www.scientific.net/amr.955-959.951.
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The transport of pathogenic bacteria from wastewater treatment facilities in subsurface has attracted extensive concerns over recent decades, while the impact of effluent water chemistry remains unclear. The influence of retention time in effluent from a municipal wastewater treatment plant on bacterial surface properties and deposition ofEscherichia colistrains in saturated quartz sand packed-bed columns was investigated in this paper. Retentions in effluent significantly altered bacterial surface properties, such as zeta potential, surface charge and hydrophobicity, subsequently changed their deposition rate coefficients and attachment efficiencies in quartz sand packed-bed columns. Under low ionic strength conditions, bacterial deposition onto quartz sand grains was in agreement with the predictions of DLVO theory, in which the secondary energy minimum was demonstrated to be predominant.
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Mah, Yau Seng, Amy Ee Ling Wong, and Fang Yenn Teo. "Modelling of Grassed Road Divider as Bio-Retention System for Urban Road Drainage." Journal of Applied Science & Process Engineering 5, no. 2 (September 30, 2018): 266–76. http://dx.doi.org/10.33736/jaspe.909.2018.
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An evaluation on the applicability of bio-retention system in grassed road divider under high rainfall of equatorial region was conducted by developing computer-aided stormwater models using USEPA SWMM 5.1. The models simulated road runoffs with and without bio-retention systems. A single unit of bio-retention system tested here was 3 m in width, 6 m in length with 150 mm of ponding depth and 600 mm of soil/storage depth. Results indicated that soil types of loamy sand, sandy loam and loam showed similar performance in reducing runoff. With installation of bio-retention system, road runoff could be reduced 40-50% when subjected to 60 minutes of 2-, 5- and 10-year ARI rain events. The results obtained from the simulation were encouraging that bio-retention system in grassed road divider could function to augment the existing urban road drainage.
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Lee, Kyo-Suk, Dong-Sung Lee, Hyun-Gyu Jung, Sang-Phil Lee, Jin-Hee Ryu, Woo-Jung Choi, Jae-Eui Yang, and Doug-Young Chung. "Evaluation of Pedotransfer Functions for Estimating Soil Water Retention Curve of Ap Horizon Soils for Various Soil Series of Reclaimed Tidal Flat Soil." Agronomy 12, no. 7 (June 23, 2022): 1507. http://dx.doi.org/10.3390/agronomy12071507.
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This investigation was to evaluate the applicability and prediction accuracy of pedotransfer function (PTF) to estimate the water retention curves of Ap horizon soils for five soil series which cannot be directly used to cultivate upland crops other than rice because of their high salinity. Soil water retention curves (SWRCs) were obtained from 150 undisturbed soil samples collected from the Ap horizons of which soil textures were grouped into sandy loam with high contents of sand (>60%) and low clay contents (<10%) and silt loam with relatively high silt content (>60%) and low sand content (<10%). Soil-water retention characteristics between 0 to −50 kPa and −50 to −1500 kPa were measured using the sandbox, kaolin-plate, and pressure chamber methods, respectively. The SWRCs were also estimated by Rawls and Brakensiek PTF (RB-PTF). The measured SWRCs of sandy loam and silt loam were compared against those obtained from RB-PTF. The SWRCs estimated with the modeled data closely fit the measured data of sandy loam and silt loam although saturated volume water content (θs) and residual volume water content (θr) of RB-PTF were higher than those of the measured mean for both soil textures. The air entry point (α) and the steepness of the water-retention curve (n) were higher in sandy loam than those of silt loam. SWRCS estimated by the RB-PTF yielded the best fit of all soil samples from the five series, whereas the MBE values less than zero indicate that θv measured at the water potentials is under-predicted. The r2 values greater than 0.9 for sandy loam and silt loam represent RB-PTF and are suitable for predicting SWRCs in RTFS because the measured data points do not vary around the estimated regression line.
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Taylor, D. H., C. F. Williams, and S. D. Nelson. "Water Retention in Root-zone Soil Mixtures of Layered Profiles Used for Sports Turf." HortScience 32, no. 1 (February 1997): 82–85. http://dx.doi.org/10.21273/hortsci.32.1.82.
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Where coarse-textured materials, such as gravel, underlie the root-zone layer of sports turf soil profiles, water retention in the root-zone layer is increased. The objective of this research was to determine the water retention characteristics in sand and sand: peat mixtures placed over coarse-textured layers and to determine how sand particle size and type of peat in the mixtures influenced water distribution after drainage. Soil profiles consisted of 30 cm of sand or sand: peat mixtures over 5 cm of predominantly coarse and very coarse sand, which in turn was over 10 cm of gravel. Excess water was added to the profile and allowed to drain for 24 or 48 h, following which water content and air-filled porosity (AFP) in the mixtures were evaluated. Regardless of the root-zone mixture, the coarse-textured sublayers resulted in a wet zone in the lower portion of the root-zone mixture. An unamended, predominantly medium and coarse sand, when used in the 30- cm root-zone layer, maintained ≈10% AFP in the lower 6 cm after drainage. Sand: peat mixtures using this sand generally maintained 3% to 8% AFP in the lower 12 cm of the root-zone layer. An unamended, predominantly fine and medium sand root-zone layer had ≈6% AFP in the lower 9 cm and sand: peat mixtures using this sand had <5% AFP in the lower 12 to 18 cm of the root-zone layer, with significant portions remaining at or near saturation after 24 or 48 h of drainage.
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Ahad, Nur Aqilah, Morteza Jami, and Stephen Tyson. "A review of experimental studies on sand screen selection for unconsolidated sandstone reservoirs." Journal of Petroleum Exploration and Production Technology 10, no. 4 (January 2, 2020): 1675–88. http://dx.doi.org/10.1007/s13202-019-00826-y.
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AbstractSand production is a problem that affects hydrocarbon production from unconsolidated sandstone reservoirs. Several factors, such as the strength of the reservoir, its lithification and cementation and reduction in pore pressure, may cause sand to be separated from the rock and transported by hydrocarbons to the well. Producing sand commonly causes erosion and corrosion of downhole and surface equipment, leading to production interruptions and sometimes forces operators to shut-in wells. Several different methods of sand control are available to reduce the impact of sand production. The reviewed papers suggest that the most suitable methods for unconsolidated sandstone reservoirs are stand-alone screens and gravel packs. Because of the cost and complexity of gravel packs, stand-alone screens are usually the first choice. These screens have different geometries, and selection of the most suitable screen depends on the particle size distribution of the grains in the formation and other reservoir and production parameters. A screen retention test, run in a laboratory with screen samples and typical sands, is often used to ensure that the screen is suitable for the reservoir. This paper reviews the main causes of sand production, the properties of unconsolidated sandstones that predispose reservoirs to sand production problems and the selection criteria for the most suitable mitigation method. The process of selecting a screen using experimental screen retention tests is reviewed, and the limitations of these tests are also discussed. Some numerical simulations of experimental tests are also reviewed, since this represents a very cost-effective alternative to laboratory experiments.
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Liu, Li, Renhe Zhang, and Zhiyan Zuo. "The Relationship between Soil Moisture and LAI in Different Types of Soil in Central Eastern China." Journal of Hydrometeorology 17, no. 11 (November 1, 2016): 2733–42. http://dx.doi.org/10.1175/jhm-d-15-0240.1.
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Abstract As important parameters in the land–atmosphere system, both soil moisture (SM) and vegetation play a significant role in land–atmosphere interactions. Using observational data from clay and sand stations over central eastern China, the relationship between leaf area index (LAI) and SM (LAI–SM) in different types of soil was investigated. The results show that the LAI–SM correlation is significantly positive in clay but not significant in sand. The physical causes for the discrepant LAI–SM correlations in different types of soil were explored from the perspectives of evapotranspiration (ET) and soil water retention. In clay stations, increasing LAI is associated with greater soil-water-retention capacity. Although the increasing LAI corresponds to increasing ET, the impact of ET on SM is weak because of the small particle size of soil. Consequently, the LAI–SM relationship in clay is significantly positive. In sand stations, ET is negatively correlated with SM owing to the large soil particle size, resulting in a negative LAI–SM correlation in sand. However, soil water retention is weakened by the increased LAI, which may be an important factor causing the insignificant LAI–SM correlation in sand.
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Touch, Narong, Tadashi Hibino, and Shinya Nakashita. "Permeability Reduction by Sediment Retention in Saturated Sand Columns." Transport in Porous Media 98, no. 3 (April 23, 2013): 615–30. http://dx.doi.org/10.1007/s11242-013-0163-9.
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Manichand, R. N. N., and R. S. S. Seright. "Field vs. Laboratory Polymer-Retention Values for a Polymer Flood in the Tambaredjo Field." SPE Reservoir Evaluation & Engineering 17, no. 03 (May 29, 2014): 314–25. http://dx.doi.org/10.2118/169027-pa.
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Summary During a polymer flood, polymer retention can have a major impact on the rate of polymer propagation through a reservoir, and consequently on oil recovery. A review of the polymer-retention literature revealed that iron and high-surface-area minerals (e.g., clays) dominate polymer-retention measurements in permeable rock and sand (>100 md). A review of the literature on inaccessible pore volume (IAPV) revealed inconsistent and unexplained behavior. A conservative approach to design of a polymer flood in high-permeability (>1 darcy) sands would assume that IAPV is zero. Laboratory measurements using fluids and sands associated with the Sarah Maria polymer flood in Suriname suggested polymer retention and IAPV values near zero [0±20 μg/g for retention and 0±10% pore volume (PV) for IAPV]. A procedure was developed using salinity-tracer and polymer concentrations from production wells to estimate polymer retention during the Sarah Maria polymer flood in the Tambaredjo reservoir. Field calculations indicated much higher polymer-retention values than those from laboratory tests, typically ranging from approximately 50 to 250 μg/g. Field cores necessarily represent an extremely small fraction of the reservoir. Because of the importance of polymer retention, there is considerable value in deriving polymer retention from field results, so that information can be used in the design of project expansions.
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Li, Jiuyi, Xiaokang Zhao, Xiujun Tian, Jin Li, Jelmer Sjollema, and Aimin Wang. "Retention in Treated Wastewater Affects Survival and Deposition of Staphylococcus aureus and Escherichia coli in Sand Columns." Applied and Environmental Microbiology 81, no. 6 (January 16, 2015): 2199–205. http://dx.doi.org/10.1128/aem.03740-14.
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ABSTRACTThe fate and transport of pathogenic bacteria from wastewater treatment facilities in the Earth's subsurface have attracted extensive concern over recent decades, while the impact of treated-wastewater chemistry on bacterial viability and transport behavior remains unclear. The influence of retention time in effluent from a full-scale municipal wastewater treatment plant on the survival and deposition ofStaphylococcus aureusandEscherichia colistrains in sand columns was investigated in this paper. In comparison to the bacteria cultivated in nutrient-rich growth media, retention in treated wastewater significantly reduced the viability of all strains. Bacterial surface properties, e.g., zeta potential, hydrophobicity, and surface charges, varied dramatically in treated wastewater, though no universal trend was found for different strains. Retention in treated wastewater effluent resulted in changes in bacterial deposition in sand columns. Longer retention periods in treated wastewater decreased bacterial deposition rates for the strains evaluated and elevated the transport potential in sand columns. We suggest that the wastewater quality should be taken into account in estimating the fate of pathogenic bacteria discharged from wastewater treatment facilities and the risks they pose in the aquatic environment.
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Pernitsky, Trent, Wei Hu, Bing Cheng Si, and Lee Barbour. "Effects of petroleum hydrocarbon concentration and bulk density on the hydraulic properties of lean oil sand overburden." Canadian Journal of Soil Science 96, no. 4 (December 1, 2016): 435–46. http://dx.doi.org/10.1139/cjss-2015-0126.
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In the Alberta oil sands, sand containing less than 8% petroleum hydrocarbon (PHC) is referred to as lean oil sand (LOS) and is used as subsoil in reclamation. The objective of this study was to determine how bulk density and PHC concentration affect the hydraulic properties of LOS. The LOS was packed in soil cores at varying bulk densities and PHC concentrations, representing the range in these parameters that occur in the reclamation setting. The cores were placed on a tension table and pressure plates to measure water retention. The constant head method was used to measure the saturated hydraulic conductivity (Ks) of the LOS. Results show that increasing PHC concentration reduced the water retention of LOS due to the presence of PHCs in soil micropores. PHC concentration also had a significant effect on the van Genuchten curve fitting parameters for the water retention curve, although the shape of the curves remained similar regardless of PHC content. Furthermore, there is a significant reduction in Ks at the high bulk density and high PHC concentrations (3.25%–7.48%), compared with low PHC concentrations (0%–1.63%). Due to the reduced Ks with increased PHCs and bulk density, LOS used as the base material in reclamation will reduce percolation and increase water storage in the reclamation soil cover.
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Cen, Cheng Xian, Cheng Han Cen, and Jing Qi Bai. "Analyse the Difference of the Performance between Masonry Mortar Mixed with Manufactured Sand and Natural Sand." Applied Mechanics and Materials 368-370 (August 2013): 1039–42. http://dx.doi.org/10.4028/www.scientific.net/amm.368-370.1039.
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With the development of various infrastructure construction, the demand of sand is increasing. The supply of natural sand could not meet the requirements of engineering due to the excessive exploitation and using the Manufactured sand which instead of natural sand is one of the effective methods to resolve the shortage of natural sand. Based on the experimental study of mechanism of used sand and natural sand masonry mortar in water retention, density and consistence, this paper analyzed the difference between the masonry mortar mixed manufactured sand and the one mixed by Natural sand. The result of study can provide the reference in engineering practice which use the masonry mortar mixed manufactured sand not but mixed by Natural sand.
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Nikooee, Ehsan, Rasoul Mirghafari, Ghassem Habibagahi, Alireza Ghadamgahi Khorassani, and Amir Mohammad Nouri. "Determination of soil-water retention curve: an artificial intelligence-based approach." E3S Web of Conferences 195 (2020): 02010. http://dx.doi.org/10.1051/e3sconf/202019502010.
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Soil Water Retention Curve (SWRC) is a fundamental relationship in unsaturated soil mechanics, knowledge of which is essential for determining major mechanical and hydraulic properties of unsaturated soils. There are several empirical, semi-empirical and physically-based models which have been proposed to date for estimating SWRC. While the physically-based models which employ the basic soil characteristics such as grain-size and pore-size distributions are regarded superior to purely empirical models, their Achilles’ heel is the several simplifying assumptions based on which these models are constructed, thereby, restricting their applications and influencing their accuracy. Given the complexity of the soil porous structure, one may resort to the new inference techniques rather than mechanistic modelling to find the relationship among soil physical characteristics and the retention properties. Therefore, an alternative approach to purely empirical relationships as well as physically-based and conceptual models for determining SWRC is the use of Artificial Intelligence (AI) based techniques to acquire a relationship for SWRC based on the soil basic properties, especially grain size distribution and porosity. Among AI-based methods, Multi-Gene Genetic Programming (MGGP), often used to establish a close form equation for a complex physical system, offers a suitable alternative to the current approaches. In this study, a database compromising of 437 soils (containing various soil types, namely, sand, clay, silt, loam, silt loam, clay loam, sandy loam, sandy clay loam, silty clay loam, silty clay, and loamy sand soils) was used along with MGGP to establish a relationship among suction, saturation, porosity and grain size distribution. The proposed equation had a reasonable agreement with the experimental data compared to the other grain-based and physically-based models.
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Zakeri, J. A., M. Esmaeili, and M. Fathali. "Evaluation of humped slab track performance in desert railways." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 225, no. 6 (June 15, 2011): 566–73. http://dx.doi.org/10.1177/0954409711403677.
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The movement of sand dunes in desert railways has various harmful effects on conventional ballasted tracks. Ballast layer solidification and line closure due to the retention of sands are major problems in such areas. In this study, a new superstructure called ‘humped slab track’ is introduced which can obviate the main problems for desert railway tracks to a significant extent. This system applies the main advantage of the ballastless track which is theballast layer's elimination for avoiding the filling of ballast voids via sand dunes. Moreover, the rail seats in this superstructure were elevated above the slab level by means of reinforced concrete protuberances called humps. Hence, the transmission of sand dunes occurred through the transverse channels between the humps and beneath the rails. To demonstrate the efficiency of the proposed system, several multi-phase fluid simulations (involving solid sand particles and air) were accomplished using the computational fluid dynamic method. The results obtained for the maximum sand flow conditions show that the ballasted track needs to be closed after a very short time whereas the humped slab track is capable of enduring considerable sand flow conditions without any need for line closure.
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Emerson, WW. "Water-retention, organic-C and soil texture." Soil Research 33, no. 2 (1995): 241. http://dx.doi.org/10.1071/sr9950241.
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Samples taken from the two textural phases of the surface soil of an irrigated natrixeralf and its clay subsoil were dried at wilting point and in air. Water retention increased linearly with C content, with values extrapolated to zero C content proportional to clay content. Emerson et al. (1994) (Aust. J. Soil Res., 32, 939-51) had already shown that water held by the surface samples at 10 kPa suction increased approximately linearly with C content, independently of clay content. Similar linear relations were deduced for other soils using values of field capacity and wilting point reported in the literature. A constant amount of water is considered to be held by portions of the silt/clay matrix. As the C content of the soil is increased, polysaccharide gels gradually fill additional 1-3 �m wide pores within the portions. It was calculated that, after a long period in grass, gel present increases available water on a weight basis, by 34% and 125% in loamy sand and sandy clay A horizons respectively. Where farmyard manure (FYM) was incorporated, gel only formed from the added C. Nevertheless the large increase in field capacity of a sandy loam produced by rotavation was temporarily preserved by prior addition of FYM. It is suggested that the gel here was mainly on microbial filaments.
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Yu, Chun Hui, Gu Hua Li, Jin Liang Gao, Bo Lan, Qun Wei, and Da Zhen Xu. "Effect of Bentonite on the Performance of the Limestone Manufactured-Sand Mortar." Applied Mechanics and Materials 357-360 (August 2013): 1374–78. http://dx.doi.org/10.4028/www.scientific.net/amm.357-360.1374.
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In order to improve workability of manufactured-sand mortar, limestone manufactured-sand mortar mixed with bentonite, and discussed the role of different dosage of bentonite that had played on mortar fluidity, consistency, layered degree ,mortar compressive and flexural strength. The results show that, mortar water demand increases, fluidity, consistency, stratification decreases with increasing bentonite dosage. Bentonite can be good to improve the water retention properties of the mortar. Doped bentonite mortar strength improved, when doped with 0.9%, mortar has best water retention, flexural, compressive strength also reached maximum.
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Underdown, David R., and Sam Hopkins. "Design and Implementation of Retention/Filtration Media for Sand Control." SPE Drilling & Completion 23, no. 03 (September 1, 2008): 235–41. http://dx.doi.org/10.2118/103782-pa.
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Kellman, Martin, and Nigel Roulet. "Nutrient Flux and Retention in a Tropical Sand-Dune Succession." Journal of Ecology 78, no. 3 (September 1990): 664. http://dx.doi.org/10.2307/2260891.
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TOUCH, Narong, Shinya NAKASHITA, Takeshi KOEDA, and Tadashi HIBINO. "Retention Model of Sediment under Groundwater Flow in Sand Beds." Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering) 68, no. 2 (2012): I_1086—I_1090. http://dx.doi.org/10.2208/kaigan.68.i_1086.
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Yasuda, H., K. Takuma, and T. Fukuda. "Water Retention Changes of Dune Sand due to Zeolite Additions." Journal of Agricultural Meteorology 52, no. 5 (1997): 641–44. http://dx.doi.org/10.2480/agrmet.52.641.
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Gamage, D. N. Vidana, R. B. Mapa, R. S. Dharmakeerthi, and A. Biswas. "Effect of rice-husk biochar on selected soil properties in tropical Alfisols." Soil Research 54, no. 3 (2016): 302. http://dx.doi.org/10.1071/sr15102.
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Despite the large number of studies on biochar and soil properties, few studies have investigated the effects of biochar in contrasting soils. A study was conducted including four rice-husk biochar rates (0%, 0.1%, 0.5% and 1%) to understand the effects on selected soil properties of two Alfisols (sand and sandy loam) in Sri Lanka. Significant changes in soil properties including increases in pH, cation exchange capacity (CEC), organic carbon, water retention at field capacity and saturated hydraulic conductivity, and reduction in bulk density, were observed at higher rates of biochar (0.5% and 1%). Mean-weight-diameter increased only at 1% biochar application rate in sandy soil, whereas it significantly increased across all the rates in sandy loam soil over the control. Electrical conductivity showed no significant increase in either soil, indicating no threat of salinity. Biochar showed a potential for ameliorating acidity, especially in slightly acidic sandy soil. Soil aggregation and water flow improved markedly in sandy loam soil over sandy soil. Further, CEC and water retention of sandy soil had pronounced effects compared with sandy loam soil. Our study highlights the importance of soil type in determining the value of rice-husk biochar as a soil amendment to improve soil aggregation, water retention and flow and CEC.
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Tananykhin, Dmitry, Maxim Grigorev, Maxim Korolev, Timur Solovyev, Nikolay Mikhailov, and Mark Nesterov. "Experimental Evaluation of the Multiphase Flow Effect on Sand Production Process: Prepack Sand Retention Testing Results." Energies 15, no. 13 (June 25, 2022): 4657. http://dx.doi.org/10.3390/en15134657.
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This paper considers a field with high-viscosity oil in a terrigenous weakly consolidated reservoir (sandstone) with a massive gas cap and an aquifer. The major challenge in the field operation is the migration of solid sand particles into the well, accompanied by a breakthrough of water and/or gas. The goal of the investigation was to evaluate the degree of influence on the sanding process of water and gas shares in the produced fluid and to determine the effect of pressure drop. The research methodology is based on a series of filtration experiments on small-sized bulk reservoir models. Particle size distribution of bulk models was created in accordance with that of the reservoir. The experiments were made in the form of Prepack Sand Retention Tests (SRT). Gas breakthrough allows sand production on a relatively high level for a longer amount of time, even though the concentration of solids in the produced fluid is lower than that of water breakthrough. On the other hand, water breakthrough triggers higher sand production, but it rapidly decreases as time goes on. Retained permeability of the model-screen system from the drawdown pressure (pressure gradient) and phase distribution of the flow were investigated. Moreover, a methodology has been developed for conducting filtration tests on bulk reservoir models to evaluate the efficiency of different screens (wire-wrapped screens, in particular).
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Ajayi, Ayodele Ebenezer, and Rainer Horn. "Comparing the potentials of clay and biochar in improving water retention and mechanical resilience of sandy soil." International Agrophysics 30, no. 4 (October 1, 2016): 391–99. http://dx.doi.org/10.1515/intag-2016-0009.
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Abstract Changing climate is threatening rainfall regularity particularly in the semi-arid and arid regions; therefore, strategies to conserve water within their coarse-grained soils and to improve water use efficiency of crops are critical. This study compared the effectiveness of biochar and two types of clay materials in augmenting water retention and improving mechanical resilience of fine sand. The amendment of fine sand with woodchip-biochar and kaolinite (non-swelling clay) and Na-bentonite (swelling clay) improved the water retention capacity and interparticle bonding of the substrate depending of the rate of amendment and water content of the substrates. Na-bentonite was more effective at increasing water retention capacity at more negative matric potentials. Biochar was more effective at saturation due to the increased porosity, while kaolinite responds similarly to biochar. It is, however, shown that most of the water retained by the Na-betonite may not be available to plants, particularly at high amendment rate. Furthermore, the clay and biochar materials improved particle bonding in the fine sand with the Na-bentonite being more effective than biochar and kaolinite (in that order) in strengthening interparticle bonds and improving the resilience of fine sand, if the rate of amendment is kept at ≤50 g kg-1.
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Razak, Nurul Nadhirah Abd, Said Jadid Abdulkadir, Mohd Azuwan Maoinser, Siti Nur Amira Shaffee, and Mohammed Gamal Ragab. "One-Dimensional Convolutional Neural Network with Adaptive Moment Estimation for Modelling of the Sand Retention Test." Applied Sciences 11, no. 9 (April 22, 2021): 3802. http://dx.doi.org/10.3390/app11093802.
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Stand-alone screens (SASs) are active sand control methods where compatible screens and slot sizes are selected through the sand retention test (SRT) to filter an unacceptable amount of sand produced from oil and gas wells. SRTs have been modelled in the laboratory using computer simulation to replicate experimental conditions and ensure that the selected screens are suitable for selected reservoirs. However, the SRT experimental setups and result analyses are not standardized. A few changes made to the experimental setup can cause a huge variation in results, leading to different plugging performance and sand retention analysis. Besides, conducting many laboratory experiments is expensive and time-consuming. Since the application of CNN in the petroleum industry attained promising results for both classification and regression problems, this method is proposed on SRT to reduce the time, cost, and effort to run the laboratory test by predicting the plugging performance and sand production. The application of deep learning has yet to be imposed in SRT. Therefore, in this study, a deep learning model using a one-dimensional convolutional neural network (1D-CNN) with adaptive moment estimation is developed to model the SRT with the aim of classifying plugging sign (screen plug, the screen does not plug) as well as to predict sand production and retained permeability using a varying sand distribution, SAS, screen slot size, and sand concentration as inputs. The performance of the proposed 1D-CNN model for the slurry test shows that the prediction of retained permeability and the classification of plugging sign achieved robust accuracy with more than a 90% value of R2, while the prediction of sand production achieved 77% accuracy. In addition, the model for the sand pack test achieved 84% accuracy in predicting sand production. For comparative model performance, gradient boosting (GB), K-nearest neighbor (KNN), random forest (RF), and support vector machine (SVM) were also modelled on the same datasets. The results showed that the proposed 1D-CNN model outperforms the other four machine learning models for both SRT tests in terms of prediction accuracy.
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Deka, Abhijit, and Sreedeep Sekharan. "Contaminant retention characteristics of fly ash–bentonite mixes." Waste Management & Research: The Journal for a Sustainable Circular Economy 35, no. 1 (October 14, 2016): 40–46. http://dx.doi.org/10.1177/0734242x16670002.
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It is important to determine the contaminant retention characteristics of materials when assessing their suitability for use as liners in landfill sites. Sand–bentonite mixtures are commonly used as liners in the construction of landfill sites for industrial and hazardous wastes. Sand is considered to be a passive material with a negligible chemical retention capacity; fly ash, however, offers the additional advantage of adsorbing the heavy metals present in landfill leachates. There have been few studies of the contaminant retention characteristics of fly ash–bentonite mixes. The study reported here determined the contaminant retention characteristics of different fly ashes, bentonite and selected fly ash–bentonite mixes for Pb2+ using 24 h batch tests. The tests were conducted by varying the initial concentrations of metal ions under uncontrolled pH conditions. The efficiency of the removal of Pb2+ by the different types of fly ash and fly ash–bentonite mixes was studied. The influence of multiple sources of fly ash on the retention characteristics of fly ash–bentonite mixes was investigated.
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Nguen, Chung, Thi Nguen, and Thi Mai. "BARRIER CHARACTERISTICS OF SANDS IN THE PROTECTION OF ENVIRONMENTAL WITH POLLUTION PETROLIUM PRODUCTS." Modern Technologies and Scientific and Technological Progress 1, no. 1 (May 17, 2021): 264–65. http://dx.doi.org/10.36629/2686-9896-2021-1-1-264-265.
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The efficiency of absorption of gasoline and motor lubricating oil through sand layers
is investigated. The influence of different heights of sand layers on the degree of retention of petrole um products is considered. The results obtained, which reached more than 80% at a layer height of 8
cm, allow assessing the barrier role of sand in preventing oil pollution of soils and reservoirs.
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Wang, Chenxi, Mohammad Haftani, Jesus David Montero Pallares, and Alireza Nouri. "An Improved Set of Design Criteria for Slotted Liners in Steam Assisted Gravity Drainage Operation." Energies 13, no. 21 (October 30, 2020): 5685. http://dx.doi.org/10.3390/en13215685.
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Slotted liners are widely used in steam-assisted gravity drainage (SAGD) wells to control sand production and sustain wellbore productivity. The slotted liner can provide desirable performance when appropriately designed. A literature review indicates a limited number of studies that offer design criteria specifically for SAGD wells. Moreover, past criteria seem to neglect some key factors, which may lead to inadequate slot design. This paper proposes a set of graphical design criteria for slotted liners in SAGD production wells, using prepacked sand retention testing (SRT) data. The SRT is designed to incorporate several essential factors that are not present in the past design criteria, such as slot density, steam breakthrough, and particle size distribution (PSD). The proposed design criteria are presented graphically for normal and aggressive conditions, where the aggressive condition accounts for the potential occurrence of the steam breakthrough. It is found that the upper bound of the design window is substantially lower for the aggressive condition due to the higher sand production after the steam breakthrough. The design criteria also indicate that the slotted liner is suitable only for the formations with low fines content.
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Turk, Rebecca L., Helen T. Kraus, Ted E. Bilderback, William F. Hunt, and William C. Fonteno. "Rain Garden Filter Bed Substrates Affect Stormwater Nutrient Remediation." HortScience 49, no. 5 (May 2014): 645–52. http://dx.doi.org/10.21273/hortsci.49.5.645.
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Twelve rain gardens were constructed to analyze the effectiveness of three different filter bed substrates to support plant growth and remove nutrients from urban stormwater runoff. The filter bed substrates included a sand-based substrate (sand) composed of (v/v/v) of 80% washed sand, 15% clay and silt fines, and 5% pine bark; a soil-based substrate (soil) composed of (v/v) 50% sandy loam soil and 50% pine bark; and a slate-based substrate (slate) composed of (v/v) 80% expanded slate and 20% pine bark. Coarse particles (6.3 to 2.0 mm) in the soil-based substrate created a large-pore network that conducted stormwater more quickly into and through the rain garden than slate or sand as evidenced by the high infiltration and saturated hydraulic conductivity values. Sand had good overall retention of pollutants except nitrogen (N) possibly as a result of the very small percentage (5%) of organic matter and low cation exchange capacity (CEC). Soil had the lowest remediation of phosphorus (P) and highest concentration of P in its effluent and was similar in N removal efficiency to slate. Slate had the best retention of N and P. Overall, all three substrates functioned in reducing the quantity of pollutants in urban stormwater runoff; yet, the impact of substrate on remediation appeared to lessen by Season 2 because there were few differences between substrate in the effluent nutrient concentration. Substrate did not affect shoot or root growth. Eleven of the 16 species (B. nigra, B. ‘Duraheat’, M. virginiana, M. ‘Sweet Thing’, I. virginica, I. ‘Henry’s Garnet’, J. effusus, P. ‘Shenandoah’, H. angustifolius, H. ‘First Light’, and E. purpureum subsp. maculatum) grew well in the rain gardens and could be used as rain garden plants.
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SCALON, SILVANA P. Q., TATIANE S. JEROMINI, ROSILDA M. MUSSURY, and DAIANE M. DRESCH. "Photosynthetic metabolism and quality of Eugenia pyriformis Cambess. seedlings on substrate function and water levels." Anais da Academia Brasileira de Ciências 86, no. 4 (December 2014): 2039–48. http://dx.doi.org/10.1590/0001-3765201420130249.
Full textAbstract:
The aim of this research was to evaluate the quality and photosynthetic metabolism of “uvaia” seedlings (Eugenia pyriformis Cambess.) on different substrates and water regimes. The seeds were sown in tubes of 50 x 190 mm in the following substrates: Sand (S), Latosol + Sand (L + S) (1:1), Latosol + Sand + Semi Decomposed Poultry Litter (L + S1 + PL) ( 1:1:0.5), Latosol + Sand + Semi Decomposed Poultry Litter (L + S2 + PL) (1:2:0.5), Latosol + Bioplant® (L + B) (1:1), and the water levels assessed were 50, 75 and 100% of water retention capacity. At 60, 90, 120 and 150 days the seedlings were evaluated according to their chlorophyll index, leaf area (cm2) and Dickson Quality Index (DQI) and at 150 days their internal concentration of carbon (mol m–2 s–1), stomatal conductance (mol m–2 s–1), transpiration rate (mmol m–2 s–1), photosynthesis (µmol m–2 s–1) and efficiency of water use (µmol de CO2 / mmol de H2O). Until their 150th days, the seedlings had higher quality and photosynthetic metabolism when cultured with substrates containing latosol + sand + poultry litter on the two variations assessed and water retention capacity of 50%.